Heat exchange apparatus

ABSTRACT

A heat exchange apparatus comprises a heat exchanging portion being disposed so as to surround the outer peripheral surface of a columnar or cylindrical heat exchange target, wherein the heat exchanging portion comprises therein a hollow space for passing heat medium therethrough and is so flexible as to expand toward at least the inner peripheral side by pressure of the heat medium. Heat medium is fed to the heat exchanging portion by a pump. By introducing the heat medium into the heat exchanging portion, the heat exchanging portion expands toward the inner peripheral side, and an inner surface of the heat exchanging portion close contacts with the outer peripheral surface of the heat exchange target, thereby greatly enhancing the heat transfer efficiency. When using a hydrogen storage/discharge container in which hydrogen storage alloy is accommodated as the heat exchange target, hydrogen storage or discharge can be efficiently carried out.

This application is based on Japanese Patent Application No. 2005-074520, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchange apparatus for efficiently cooling or heating a hydrogen storage container for accommodating hydrogen storage alloy therein, etc.

2. Description of the Related Art

The hydrogen storage alloy has a feature that heat is generated when hydrogen is absorbed, so that the hydrogen absorption reaction is not continued unless the heat is removed by some method, and also the hydrogen absorption rate is also greatly affected by the heat removing speed. With respect to a hydrogen stocking container that uses hydrogen storage alloy and has no cooling pipe for passing medium such as water or the like therethrough (hereinafter MH canister), a cooling method for cooling through the surface of the surface layer of the MH canister is adopted.

As the cooling method through the surface layer surface is normally adopted a method of directly immersing the surface of MH canister with fluid such as air, water or the like, a method of blowing the fluid to the surface of the MH canister, or a method of carrying out cooling through a cooling jacket or the like that is formed of metal or the like in conformity with the shape of the MH canister and through which a medium is passed.

FIG. 4 shows an example of a direct cooling apparatus using a medium tank.

A medium bath 10 has a take-in port 11 for liquid medium, and a discharge port 12 for the liquid medium, and they are connected to a medium tank 15 through a medium pipe 13. A pump 16 is interposed between the medium tank 15 and the take-in port 11 in the medium pipe 13. The above structure makes it possible to circulate the liquid medium 20 between the medium tank 15 and the medium bath 10. The medium tank 15 is provided with a thermostat device 17, and the thermostat device 17 adjusts or cools the liquid medium to a predetermined temperature. A device group shown in FIG. 18 may be replaced by the supply of city water from a tap for tap water.

Furthermore, hydrogen storage alloy (not shown) is accommodated in the MH canister 1 immersed in the medium bath 10, and a hydrogen pipe 2 is connected to the MH canister 1 so that ventilation can be performed between the MH canister 1 and the hydrogen pipe 2. A hydrogen supply device (or steel cylinder) 5 is connected to the other end of the hydrogen pipe 2 through a shut-off valve 3 and a pressure adjusting valve 4.

Next, the operation of the direct cooling apparatus will be described.

The apparatus is classified into a medium pipe system and a hydrogen pipe system. The medium pipe system is mainly constructed by the medium bath 10, a thermostat bath 17, a pump 16 and a medium pipe 13 for connecting the respective parts, and functions as a cooling apparatus.

The MH canister 1 is disposed in the medium bath 10, and liquid medium 20 which is adjusted in temperature or cooled in the thermostat device 17 is fed through the medium pipe 13 to the medium bath 10 by a pump 16. The liquid medium introduced from the take-in port 11 of the medium bath 10 into the medium bath 10 cools the surface of the MH canister 1 while moving upwardly in the medium bath 10, and overflows from the discharge port 12 of the medium bath 10. The liquid medium which increases in temperature due to heat exchange with the MH canister 1 and overflows is returned through the medium pipe 13 to the medium tank 15, adjusted in temperature and then circulated through the medium pipe by the pump 16 again to cool the MH canister 1 continuously.

In the hydrogen pipe system, hydrogen which is supplied from the hydrogen supply device 5 and adjusted to some pressure by the pressure adjusting valve 4 is supplied into the MH canister 1. At this time, the shut-off valve 3 is kept open. The hydrogen storage alloy in the MH canister 1 absorbs the hydrogen amount conformed with the relationship between the hydrogen supply pressure and the hydrogen storage alloy temperature, so that hydrogen is filled in the MH canister.

In the MH canister in which the hydrogen storage alloy is filled till the center portion of the container, the alloy layer is thicker in proportion to the distance from the surface of the container to the center. This means that the heat transfer coefficient to the medium is lowered, and causes delay of the hydrogen filling time. The hydrogen absorption time between the MH canisters that are perfectly identical in the inner structure, the hydrogen storage alloy amount, etc. is dependent on the heat transfer coefficient of the surface of the MH canister except for the temperature/pressure conditions of hydrogen to be absorbed. When the medium and the medium flow amount are the same, direct cooling using no jacket is better as the method of increasing the heat transfer coefficient.

However, when the MH canister is directly cooled with safe and easily-treatable liquid medium such as water or the like except for gas medium by using the cooling apparatus described above, the surface of the MH canister is contaminated by the medium, and also it is required to clean the surface of the MH canister by wiping the surface of the MH canister or the like after the filling work is finished. With respect to gas medium such as air, etc., the contamination problem can be solved, but it has a physical property that the heat transfer coefficient thereof is small, which delays the hydrogen filling time.

On the other hand, when the metal cooling jacket is used so as to cover the surface of the MH canister, the medium contamination problem can be solved, but an air layer remains between the surface of the MH canister and the cooling jacket and it is difficult to bring the surface of the MH canister and the cooling jacket into perfectly close contact into each other, thereby causes the delay of the hydrogen filling time. Furthermore, the cooling jacket may be fastened by a screw or the like to enhance the degree of adhesion. However, there occurs a problem that not only it does not perfectly nullify the air layer, but also the number of working steps is increased.

SUMMARY OF THE INVENTION

The present invention has been implemented to solve the problem of the related art as described above, and has an object to provide a heat exchange apparatus suitable for a cooling apparatus that can shorten a hydrogen filling time without contaminating the surface of an MH canister by changing the structure and material of a jacket.

That is, according to a first aspect of the invention, a heat exchange apparatus comprises a heat exchanging portion being disposed so as to surround an outer peripheral surface of a columnar or cylindrical heat exchange target, wherein the heat exchanging portion comprises therein a hollow space for passing heat medium therethrough and is so flexible as to expand toward at least an inner peripheral side thereof by pressure of the heat medium.

According to a second aspect of the invention, the heat exchanging portion is designed in a shape of a tube so as to be wound around the outer peripheral surface of the heat exchange target.

According to a third aspect of the invention, the heat exchanging portion is designed in a cylindrical shape so as to surround the outer peripheral surface of the heat exchange target.

According to a fourth aspect of the invention, the heat exchange target is designed to be circular in outer peripheral cross section.

According to a firth aspect of the invention, a cylindrical case for supporting the heat exchanging portion is provided at the outer peripheral side of the heat exchanging portion.

According to a sixth aspect of the invention, the heat exchange target is a hydrogen storage/discharge container in which hydrogen storage alloy is accommodated.

According to the invention, the heat exchanging portion is disposed so as to surround the outer peripheral surface of the heat exchange target, and the heat medium is introduced into the hollow space thereof, so that the heat exchanging portion expands, and the heat exchanging portion comes into close contact with the outer peripheral surface of the heat exchange target, thereby greatly enhancing the heat transfer efficiency. For example, by using cooling medium as heat medium, the heat exchange target can be effectively cooled through the heat exchanging portion. Furthermore, by using the heating medium as heat medium, the heat exchange target can be effectively heated through the heat exchanging portion. The introduction of the heat medium into the heat exchanging portion can be performed by a supply device such as a pump or the like. The heat medium is continuously introduced into the heat exchanging portion by the supply device, and the heat-exchanged heat medium is continuously discharged from the heats exchanging portion, whereby the heat exchange target is continuously heat-exchanged.

As the heat exchanging portion is selected a material having flexibility under pressure of the heat medium. The material having flexibility may be used for the overall heat exchanging portion or for only the inner peripheral side of the heat exchanging portion. The material having flexibility is not limited to a specific one in the present invention, but resin or resin-coated rubber may be used.

Furthermore, it is sufficient only that the heat exchanging portion can be disposed so as to surround the outer peripheral surface of the heat exchange target, and for example, it may be disposed by designing the heat exchanging portion in the form of a tube so that it is spirally wound around the outer peripheral surface of the heat exchange target, or by designing the heat exchanging portion in a cylindrical shape so that it is engagedly fitted to the heat exchange target.

Furthermore, the heat exchanging portion expands toward the inner peripheral side by the pressure of the heats medium introduced into the hollow space, whereby the heat exchanging portion is effectively brought into close contact with the heat exchange target to enhance the heat transfer efficiency. Accordingly, with respect to the arrangement of the heat exchanging portion to the heat exchange target, it is disposed so as to surround the heat exchange target in consideration of the degree of the expansion. Accordingly, it is desired that the heat exchange target or the heat exchanging portion is detachable when the pressure of the heat medium is eliminated or the pressure is weakened so that the arrangement of the heat exchanging portion to the heat exchange target can be released as occasion demands after the heat exchanging portion is set up.

Therefore, it is desired that the heat exchanging portion is disposed at an inner diameter which is slightly larger than the outer diameter of the heat exchange target. In order to make sure the close contact with the heat exchange target by the expansion of the heat exchanging portion, it is desired that the shape of the heat exchange target is set to a circular cylinder or column and the heat exchanging portion is disposed along the outer peripheral surface of the heat exchanging portion. Accordingly, the heat exchanging portion expansion to the inner peripheral side comes into close contact with the surface of the heat exchange target flatly and under uniform pressure. In addition, air is easily discharged from the gap between the heat exchanging portion and the heat exchange target, thereby achieving a cooling jacket having no air layer and excellent adhesiveness.

Furthermore, a cylindrical case for supporting the heat exchanging portion can be arranged at the outer peripheral side of the heat exchanging portion. When the heat exchanging portion expands toward the outer peripheral side by the pressure of the heat medium, the cylindrical case serves to restrict the expansion concerned and promote the heat exchanging portion to expand toward the inner peripheral side and come into close contact with the heat exchange target.

The heat exchange target is heat-exchanged (cooled or heated) with the outside if necessary, and it may be applicable to various fields. However, the present invention is optimally applied to a hydrogen storage alloy container which is greatly different in hydrogen storage/discharge efficiency in accordance with the heat-exchange efficiency. In the hydrogen storage alloy container, cooling or heating is effectively carried out, so that hydrogen storage or discharge can be efficiently carried out.

In the present invention, the heat exchange purpose may be both the cooling and heating, and cooling and heating may be switched to each other if necessary.

As described above, according to the present invention, there is provided the heat exchanging portion that is disposed so as to surround the outer peripheral surface of a columnar or cylindrical heat exchange target, contains therein a hollow space for passing heat medium therethrough and is so flexible as to expand toward at least the inner peripheral side by pressure of the heat medium. Therefore, the heat-exchange can be efficiently performed with the heat exchange target. Further, the following effects can be achieved.

(1) There is an effect that when heat exchange with a hydrogen storage alloy container is carried out, the hydrogen filling time can be shortened by the heat exchanging portion having no air layer and the excellent adhesiveness.

(2) There is an effect that the liquid medium does not come into contact with the heat exchange target, and thus sub-zero cooling by brine for low temperature which takes a lot of trouble to wipe the surface can be easily performed.

(3) Since the force of fastening the heat exchange target is generated by expansion of the heat exchanging portion due to the pressure of the heat medium, and thus the heat exchange target can be prevented from dropping off and thus can be fixed. When the flow of the medium is stopped, the liquid pressure is nullified, and also the expansion of the heat exchanging portion is stopped, so that the heat exchange target can be easily taken out. That is, there is an effect that the heat exchange target is brought with high detachability.

(4) Neither a jacket fastening work nor a fixing work is needed, and thus the working step number can be reduced.

(5) There is an effect that not only cooling, but also heating can be performed by likewise varying the medium temperature

(6) There is an effect that the present invention can be used for the efficient surface heating/cooling in various fields.

(7) There is an effect that the present invention can be used for positioning and fixing of parts.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a heat exchange apparatus according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view showing a heat exchange apparatus according to another embodiment;

FIG. 3 is a graph showing the comparison in hydrogen filling amount and filling time among the cooling apparatus of the present invention, the direct cooling apparatus and the cooling apparatus based on the metal water cooling jacket; and

FIG. 4 is a diagram showing a case where a related direct cooling apparatus is used.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A cooling apparatus according to an embodiment of the present invention will be described with reference to FIG. 1.

The cooling apparatus is equipped with a cylindrical case 7 having a take-in port 6 for liquid medium and a discharge port 8 for liquid medium, and a medium pipe 13 is connected to the take-in port 6 and the discharge port 8 from the outside of the cylindrical case 7. The medium pipe 13 is connected to a medium tank 15 through a pump 16, and the above structure circulates the liquid medium 20 serving as heat medium between the medium tank 15 and the cylindrical case 7. A thermostat device 17 is affixed to the medium tank 15, and adjust the temperature of the liquid medium 20 to a predetermined temperature. A device group indicated by reference numeral 18 may be replaced by tap water supply.

An MH canister 1 serving as a heat exchange target disposed in the cylindrical case 7 is designed in a cylindrical form, and sealed at both the ends thereof. Hydrogen storage alloy (not shown) is accommodated therein. In the MH canister 1, a hydrogen pipe 2 is connected to the MH canister 1 from the outside so that ventilation can be performed between the hydrogen pipe 2 and the hydrogen storage alloy. The hydrogen pipe 2 is connected to a hydrogen supply device 5 through a shutoff valve 3 and a pressure adjusting valve 4. A hydrogen pipe system is constructed as described above.

In the cylindrical case 7, a resin tube 9 serving as a heat exchanging portion is spirally wound and disposed in the cylindrical shape so as to achieve an inner peripheral diameter which is slightly larger than the outer peripheral diameter of the MH canister 1, and both the end portions of the tube 9 are connected to the take-in port 6 and the discharge port 8. The outer peripheral side of the tube 9 is substantially along the inner peripheral surface of the cylindrical case 7, and it is supported by the cylindrical case 7. The tube 9 has such flexibility that by making the heat medium flow through the tube 9, the tube 9 increases in diameter and expands by the pressure of the heat medium. A medium pipe system is constructed by the medium tank 15, the medium pipe 13, the pump 16, the thermostat device 17, the cylindrical case 7 and the tube 9.

Next, the operation of the apparatus will be described.

First, the MH canister 1 is disposed at the center of the inner peripheral side of the resin tube 9 which is spirally wound in the cylindrical case 7. The liquid medium which has been adjusted in temperature or cooled in the thermostat device 17 is passed through the medium pipe 13 and fed to one end of the spirally wound resin tube 9 by the pump 16. The liquid medium 20 passed through the take-in port 6 and introduced into the hollow space of the resin tube 9 flows from the other end side to the discharge port 8 side along the spiral path of the tube 9.

The liquid medium 20 has pressure because of the discharging action of the pump 16, and thus it spreads the inner diameter of the resin tube 9 having flexibility. Accordingly, the inner peripheral side of the resin tube 9 comes into contact with the outer peripheral surface of the MH canister 1. At this time, the neighboring turns of the spiral resin tube 9 likewise expand to each other, and thus the cross-section of the resin tube 9 is designed in a semi-cylindrical shape so that the MH canister 1 side thereof is a flat surface. In addition, the spiral overall internal efficiently comes into close contact with the surface of the MH canister 1 because of the relationship between the air discharging performance and the liquid pressure at the contact face. This contributes to prevention of reduction of the heat transfer area and increase of the heat transfer coefficient due to the close contact, so that the efficient heat exchange between the liquid medium 20 and the MH canister 1 can be performed. At this time, the expansion of the resin tube 9 to the outer peripheral side is restricted by the cylindrical case 7, and the close contact of the inner peripheral side of the resin tube 9 with the MH canister 1 is promoted.

The liquid medium 20 which has completed the heat-exchange in the spiral resin tube 9 is returned to the medium tank 15 through the discharge port 8 and the medium pipe 13, and adjusted in temperature by the thermostat device 17. Then, it is circulated by the pump 16 again, and can continuously cool the MH canister 1.

In the hydrogen pipe system, hydrogen that is supplied from the hydrogen supply device 5 and adjusted to some pressure by the pressure adjusting valve 4 is supplied to the canister 1. At this time, the shut-off valve 3 is opened. The hydrogen storage alloy in the MH canister 1 absorb the amount of hydrogen consistent with the relationship between the hydrogen supply pressure and the hydrogen storage alloy temperature to be filled with hydrogen by the efficient heat removing action of the medium pipe system described above. When the operation of the pump 16 is stopped, the introduction of the liquid medium into the tube 9 is also stopped, the expansion of the tube 9 is released, and the diameter of the tube is reduced to the original dimension. Accordingly, when it is required to detach the MH canister 1, the detaching work can be easily performed.

In the above-described embodiment, the heat exchanging portion is constructed by the spirally wound tube. In the present invention, the heat exchanging portion may be constructed by not only the tube-shaped member, but also a cylindrical-shape member. This structure will be described with reference to FIG. 2. The same constituent elements as the above-described embodiment are represented by the same reference numerals, and the description thereof is simplified.

That is, a hollow bag body 19 that is designed in a cylindrical shape and has a bottom portion as shown in FIG. 2 is prepared as a heat exchanging portion, and disposed in the cylindrical case 7 in the same manner as described above. The bag body 19 intercommunicates with the take-in port 6 at the lower end thereof, and intercommunicated with the discharge port 8 at the upper end thereof.

When the above-described apparatus is operated, the MH canister 1 is disposed at the center of the inner peripheral side of the bag body 19 so that the outer periphery of the MH canister 1 is surrounded by the bag body 19. When liquid medium is made to flow through the medium pipe 13 into the bag body 19, the liquid medium introduced through the take-in port 6 into the hollow section of the bag body 19 makes the bag body 19 expand to the inner peripheral side and come into close contact with the outer peripheral surface of the MH canister 1. The liquid medium is passed through the hollow section and discharged form the discharge port 8. By subsequently introducing the liquid medium into the bag body 19, the close contact with the outer peripheral surface of the MH canister 1 is kept, and the MH canister 1 can be efficiently cooled. At this time, the expansion of the bag body 19 to the outer peripheral side is restricted by the cylindrical case 7 as in the case of the above-described embodiment. The operation in the hydrogen pipe system is the same as the above-described embodiment. When the introduction of the liquid medium into the bag body 19 is stopped after the operation is finished, the expansion of the bag body 19 is stopped, and the MH canister 1 can be easily taken out as occasion demands.

The MH canister was cooled by using the cooling apparatus of the present invention shown in FIG. 1, a direct cooling apparatus shown in FIG. 4 and a cooling apparatus based on a metal cooling jacket, and the effect on the hydrogen filling time was tested in each of the above cases. The results are shown in the graph of FIG. 3. The abscissa axis represents the filling time (minute), and the ordinate axis represents the hydrogen filling amount (NL). The testing was carried out on the same MH canister under the condition that each of the hydrogen supply pressure, the liquid medium temperature and the liquid medium circulating flow amount was identical among the above cases. A solid line in the graph represents the result based on the direct cooling apparatus, a dotted line represents the result based on the cooling apparatus of the present invention, and a one-dotted chain line represents the result based on the metal cooling jacket apparatus.

It has been found from the graph that the cooling apparatus of the present invention can fill hydrogen in the MH canister substantially in the same filling time as the direct cooling. Furthermore, a clear difference is observed in the comparison of the filling time with the metal cooling jacket corresponding to the indirect cooling, and the effect of the present invention is sufficiently shown.

The above-described embodiment uses the liquid medium, however, it may be likewise applicable to a case where gas medium is used.

The present invention has bee described on the basis of the above-described embodiment. However, the present invention is not limited to the content of the foregoing description, and modifications may be made in the scope of the present invention. 

1. A heat exchange apparatus comprising a heat exchanging portion being disposed so as to surround an outer peripheral surface of a heat exchange target, wherein the heat exchanging portion comprises therein a hollow space for passing heat medium therethrough and is so flexible as to expand toward at least an inner peripheral side thereof by pressure of the heat medium.
 2. The heat exchange apparatus according to claim 1, wherein the heat exchanging portion is designed in a shape of a tube so as to be wound around the outer peripheral surface of the heat exchange target.
 3. The heat exchange apparatus according to claim 1, wherein the heat exchanging portion is designed in a cylindrical shape so as to surround the outer peripheral surface of the heat exchange target.
 4. The heat exchange apparatus according to claim 1, wherein the heat exchange target is designed to be circular in outer peripheral cross section.
 5. The heat exchange apparatus according to claim 1, wherein a cylindrical case for supporting the heat exchanging portion is provided at the outer peripheral side of the heat exchanging portion.
 6. The heat exchange apparatus according to claim 1, wherein the heat exchange target is a hydrogen storage/discharge container in which hydrogen storage alloy is accommodated.
 7. The heat exchange apparatus according to claim 1, wherein the heat exchanging portion is disposed so as to surround the outer peripheral surface of a columnar or cylindrical heat exchange target.
 8. The heat exchange apparatus according to claim 1, wherein the heat exchanging portion expands toward at least the inner peripheral side thereof so as to contact with the outer periphery surface of the heat exchange target by pressure of the heat medium.
 9. The heat exchange apparatus according to claim 1, wherein the heat exchanging portion is disposed at an inner diameter which is larger than an outer diameter of the heat exchange target. 